The present invention relates to a method and apparatus for charging a substrate in electrophotographic printing. More specifically, the invention relates to repairing a charging device.
In the well-known process of electrophotographic printing, the photoconductive member is electrostatically charged, and then exposed to a light pattern of an original image to selectively discharge the surface in accordance therewith. The resulting pattern of charged and discharged areas on the photoconductive member forms an electrostatic charge pattern, known as a latent image, conforming to the original image. The latent image is developed by contacting it with a finely divided electrostatically attractable powder known as xe2x80x9ctoner.xe2x80x9d Toner is held on the image areas by the electrostatic charge on the photoreceptor surface. Thus, a toner image is produced in conformity with a light image of the original being reproduced. The toner image may then be transferred to a substrate or support member (e.g., paper), and the image affixed thereto to form a permanent record of the image to be reproduced. Subsequent to development, excess toner left on the photoconductive member is cleaned from the surface thereof. The process is useful for light lens copying from an original or printing electronically generated or stored originals such as with a raster output scanner (ROS), where a charged surface may be imagewise discharged in a variety of ways.
Various types of charging devices have been used to charge or precharge photoconductive insulating layers. In commercial use, for example, are various types of corona generating devices to which a high voltage of 5,000 to 8,000 volts may be applied to the corotron device thereby producing corona spray which imparts electrostatic charge to the surface of the photoreceptor. One particular device would take the form of a single corona wire strung between insulating end blocks mounted on either end of a channel or shield.
The single corotron wire is typically very delicate. The single corotron wire has a diameter of 0.001 inches and is made of a electrical conductive material, i.e., tungsten. Installing the single corona wire onto insulating end blocks of the corona generating device is very difficult. In particular, securing the ends of the single corona wire to the corona device is particularly difficult. Utilizing typical fasteners, such as bolts and screws to secure the wire, tends to overtighten the wire causing it to break. Use of adhesive to secure the wire to the corotron device is very time consuming in that the wire must be held in position as the adhesive dries. Welding of the wire to the corotron device is found to be particularly effective in that by welding, the wire is durably secured to the housing. Also, the welding process can occur very quickly providing for rapid and inexpensive assembly of the wire onto the housing.
Recently, to ease servicing of a copy machine or printing machine, customer replaceable units (CRUs) have been designed for easy removal from the copy machine by a copy machine operator. These customer replaceable units include those components which most quickly wear within the machine. For example, the customer replaceable unit may include the marking particles or toner as well as the photoreceptor, the cleaning blade, and the corotron wire. Alternatively, the CRU may include multiple CRUs. For example, the corotron may be included in a CRU having the photoreceptor, the cleaning blade, and the corotron wire. The corotron wire is typically permanently welded to the housing of the customer replaceable unit. To permit the assembly of the customer replaceable unit, typically, the housing of the CRU is made of more than one component. One of these components has the corotron wire welded thereto.
The CRUs are changed several times during the life of the copy machine. Recently, CRUs are being remanufactured rather than being replaced as a new unit. These CRUs are inspected and wear components, for example, the cleaning blade, corotron wire and photoreceptor, may require replacement. In those situations where the corotron wire must be replaced, since the wire is integrally welded to the portion of the frame of the CRU, the frame as well as the wire must be discarded during remanufacturing. This increases the cost of remanufacturing CRUs as well as requiring a portion of the frame be discarded or recycled.
The present invention is intended to eliminate at least some of the aforementioned problems.
The following disclosures may be relevant to various aspects of the present invention:
U.S. Pat. No. 5,140,367
Patentee: Olekinski, et al.
Issue Date: Aug. 18, 1992
U.S. Pat. No. 5,181,069
Patentee: Olekinski, et al.
Issue Date: Jan. 19, 1993
U.S. Pat. No. 4,754,305
Patentee: Fantuzzo et al.
Issue Date: Jun. 28, 1988
U.S. Pat. No. 4,627,701
Patentee: Onoda et al.
Issue Date: Dec. 9, 1986
U.S. Pat. No. 4,549,244
Patentee: Driessen
Issue Date: Oct. 22, 1985
U.S. Pat. No. 3,499,143
Patentee: Martin
Issue Date: Mar. 3, 1970
U.S. Pat. No. 5,140,367 discloses a method and apparatus for fitting a replacement corotron wire onto a corona wire cartridge. The assembly includes a pair of hook type terminals. The apparatus also includes a replacement wire having a loop at each end of the wire. One of the loops engages one hook terminal and the opposing loop connects to one end of a double hook ended coil spring. The opposing coil spring hook end is mounted on the opposing hook end terminal.
U.S. Pat. No. 5,181,069 discloses a method and apparatus for fitting a replacement corotron wire onto a corona wire cartridge. The assembly includes a pair of hook type terminals and rivets to mount the terminals onto a cartridge frame. The apparatus also includes a replacement wire having a loop at each end. One of the loop engages one hook terminal and the opposing loop connects to one end of a double hook ended coil spring. The opposing coil spring hook end is mounted on the opposing hook end terminal.
U.S. Pat. No. 754,305 discloses a corona discharge device which includes a throw away subassembly. The subassembly can be assembled into the printing machine. The subassembly includes a rectangularly shaped insulative frame and a tungsten wire. The subassembly cooperates with a generally U-shaped, conductive shield to form the corona discharge device.
U.S. Pat. No. 4,627,701 discloses a corona discharge device which includes a shield case, a discharging wire and block portions on which the discharging wire is mounted. The opposite ends of the wire are fixedly secured to the blocks by rivets.
U.S. Pat. No. 4,549,244 discloses a corona generating device including a plurality of separate parallel corona wires supported between insulating end block assemblies. The wires are preferably formed from a single U-shaped wire with a closed end portion wrapped around an arcuate insulating end post and an arcuate insulating end post in the second end block assembly around which the wire is wrapped.
U.S. Pat. No. 4,792,680 discloses a corona generating device including a corona wire. A supply of corona wire of indefinite length is mounted on the corona generating device for which one ore more runs of fresh wire can be periodically withdrawn with provision of releasably holding the wire under tension during periods of use.
In accordance with one aspect of the present invention, there is provided a corona generator including a body and a first support secured to the body. The corona generator also includes a second support secured to the body and spaced from the first support. The corona generator also includes an electrode mounted to the first support and to the second support.
In accordance with a further aspect of the present invention, there is provided a customer replaceable unit of the type having a corona generator for charging a surface. The corona generator includes a body, and a first support secured to the body. The corona generator also includes a second support secured to the body and spaced from the first support. The corona generator further includes an electrode mounted to the first support and to the second support.
In accordance with another aspect of the present invention, there is provided a printing machine of the type having a corona generating device for charging a surface. The corona generating device includes a body and a first support secured to the body. The corona generator also includes a second support secured to the body and spaced from the first support. The corona generator also includes an electrode mounted to the first support and to the second support.
In accordance with yet another aspect of the present invention, there is provided a method of remanufacturing a corona device having an electrode secured to a housing. The method includes the steps of removing the electrode from the housing, mounting a first support to the housing, mounting a second support to the housing, and attaching a new electrode to the first support and to the second support.